1. Field Of The Invention
This invention relates to tamperproof packaging and, more specifically, it relates to a tamper resistant package and a method of sealing packages such that a clear indication would be given if any tampering occurs and more specifically the invention relates to a product which is coated with a layer of extremely brittle material that cannot be unsealed without completely shattering the packaging. Also provided is one embodiment of the present invention wherein part or all of the packaging is comprised of an extremely brittle material such that the packaging itself cannot be unsealed without completely shattering the packaging material.
2. Description Of The Prior Art
The tampering with and adulteration of many commercially available products has become a critical problem endangering health and sanitation. Many products which are adulterated or tampered with ultimately reach a consumer beaming no indication that such adulteration or tampering has occurred. Accordingly, it is highly desirable to provide a type of packaging which would give an indication that there has been interference with the integrity of the product packaging.
Various mechanical indications used to determine the integrity of several types of products and containers have been known. For example, U.S. Pat. No. 3,662,915 relates to a tamperproof package which provides a recessed tab in the inner periphery of a container which breaks away from the remainder of the container when entry is made into the container so as to indicate that tampering with the package has occurred.
It has been known to employ elastomeric materials disposed in protective surrounding relationship with respect to a container. See U.S. Pat. Nos. 4,546,881, 4,449,632, and 4,181,223.
U.S. Pat. No. 2,074,490 discloses a tamperproof container in the form of a tinplate container having a composite coating consisting of a heat sensitive paint, printing ink, and varnish. This coating is said to distort responsive to any effort to remove the can end, get access to the contents, and then solder the end to the can.
It has been known to provide for rupturing of outer coatings which fracture responsive to operation of a tear strip. See U.S. Pat. No. 3,415,402. See so U.S. Pat. No. 4,479,585.
It has been known to protect printed circuit boards by ultraviolet curable polymeric coatings which are intimately bonded to such boards. See U.S. Pat. Nos. 4,451,523 and 4,424,252.
In addition to such mechanical indicators, it has been known to provide a color indication that package integrity has been interrupted. For example, U.S. Pat. No. 3,935,960 provides a hermetically sealed container having a tape closure over an aperture for removing the contents of the container. The tape closure is provided with an indicator layer of color capsules which rupture when the tape closure is removed.
U.S. Pat. No. 4,502,605 provides an indicator dye/activator system which is mounted on the cap of a container in such a way that opening the cap of the container causes the indicator material to oxidize and thereby change in color. It teaches the use of a volatile alkali solution such as ammonia as an activator having a pH in the range of 9-12 whereas atmospheric air has a pH in the range of 5-7. The preferred indicator dye is said to be phenolphthalein or other dyes sensitive to changes in the pH. See also U.S. Pat. No. 4,516,679.
U.S. Pat. No. 4,098,577 also discloses use of a pH sensitive dye which will display a different color when in contact with atmospheric air which would occur when the package is opened. U.S. Pat. No. 4,505,399 provides a sheet of material sensitive to light or oxygen which would effect a time-delayed, irreversible change in appearance in response to exposure. The sensitive material would be placed between two inactive sheets and the combination would be placed over the opening to the container so that the sensitive sheet would have to be exposed when the container is opened.
Some of the problems which have been encountered in using the prior art techniques are that they can be circumvented by various means. In addition, the known methods are primarily confined to use with certain types and configurations of containers.
In spite of the existing prior art techniques, there remains a need for an effective method of indicating that a product has been tampered with or adulterated. There remains a need for such a method which is economical and easy to use with a wide range of package configurations.